The last decade has seen knowledge of the immune system and its regulation expand tremendously. One area of particular interest has been that of research on the proteins and glycoproteins which regulate the immune system. Perhaps the best known of these molecules, which are generically referred to as "growth factors", "cytokines", "leukotrines", "lymphokines", etc., is interleukin-2 ("IL-2"). See, e.g., U.S. Pat. No. 4,778,879 to Mertelsmann et al.; U.S. Pat. No. 4,490,289, to Stern; U.S. Pat. No. 4,518,584, to Mark et al.; and U.S. Pat. No. 4,851,512 to Miyaji et al. Additional patents have issued which relate to interleukin 1 - ("IL-1"), such as U.S. Pat. No. 4,808,611, to Cosman. The disclosure of all of these patents are incorporated by reference herein.
In order for molecules such as IL-2 and IL-1 to exert their effect on cells, it is now pretty much accepted that these must interact with molecules, located on cell membranes, referred to as receptors. Patents which exemplify disclosures of interleukin receptors include Honjo et al., U.S. Pat. No. 4,816,565; and Urdal et al., U.S. Pat. No. 4,578,335, the disclosures of which are incorporated by reference. Recently, Fanslow, et al., Science 248: 739-41 (May 11, 1990) presented data showing that the effect of IL-1 in vivo could be regulated via the administration of a soluble form of its receptor. The last paragraph of the Fanslow paper, the disclosure of which is incorporated by reference, describes the types of therapeutic efficacy administration of a soluble IL-1 receptor ("IL-1R") is expected to have.
The lymphokine IL-9, previously referred to as "P40", is a T-cell derived molecule which was originally identified as a factor which sustained permanent antigen independent growth of T4 cell lines. See, e.g., Uyttenhove, et al., Proc. Natl. Acad. Sci. 85: 6934 (1988), and Van Snick et al., J. Exp. Med. 169: 363 (1989), the disclosures of which are incorporated by reference, as is that of Simpson et al., Eur. J. Biochem. 183: 715 (1989).
The activity of IL-9 was at first observed to act on restricted T4 cell lines, failing to show activity on CTLs or freshly isolated T cells. See, e.g., Uyttenhove et al., supra, and Schmitt et al., Eur. J. Immunol. 19: 2167 (1989). This range of activity was expanded when experiments showed that IL-9 and the molecule referred to as T cell growth Factor III ("TCGF III") are identical. IL-9 enhances the proliferative effect of bone marrow derived mast cells to "IL-3", as is described by Hultner et al., Eur. J. lmmunol. (in press), and in U.S. patent application Ser. No. 498,182 filed Mar. 23, 1990 the disclosures of both being incorporated by reference herein. It was also found that the human form of IL-9 stimulates proliferation of megakaryoblastic leukemia. See Yang et al., Blood 74: 1880 (1989).
These results point to multiple sites for reception of the IL-9 molecule rather than one on a single type of cell. As such, the invention describes a process by which the IL-9 receptor (IL-9R") was purified and characterized. The invention also describes the thus purified and characterized IL-9R molecule, as well as methods for using the molecule.
The substantially pure IL-9R of this invention is further characterized by a molecular weight of about 64 kilodaltons. It is a glycoprotein which, upon treatment with N-glycosidase F yields a peptide having a molecular weight of about 54 kilodaltons. These data are elaborated upon and explained in the disclosure which follows.